Knife-feeding arrangements for sickle-shaped knives



Feb. 16, 1965 J. A. MASON 3,169,431

KNIFE-FEEDING ARRANGEMENTS FOR SICKLE-SHAPED KNIVES Filed March 21, 1963 2 Sheets-Sheet 1 28 l 40 41 58 Q\ 56 E? 32 39 27 35 I 23A i 23 INVENTOR A TTOR NEE Feb. 16, 1965 J. A. MASON 3,169,431

KNIFE-FEEDING ARRANGEMENTS FOR SICKLE-SHAPED KNIVES Filed March 21, 1963 2 Sheets-Sheet 2 Fig.3.

l/V l E N TOR A TTORNEX United States Patent 3,169,431 KNIFE-FEEDING ARRANGEMENTS FOR SlCKLE-SHAPED KNIVES 3 Claims. (c1. 83-356) This invention concerns improvements in knife-feeding arrangements for sickle-shaped knives in cut-offs of cigarette making machines.

As is well known, these knives are lightly ground at frequent intervals while the machine is operating. Often they are ground at each revolution of the cut-off mechanism, that is, once per cigarette cut but in the present example they are ground at rather longer intervals. In either case they wear out rather quickly and it is necessary to provide means for feeding the knife outwards from its carrier so as to compensate for the wear.

According to the invention there is provided a knifefeeding device, for a cigarette machine cut-off rotatable about an axis and having a sickleknife, of the kind comprising a knife clamp frictionaly gripping the knife, a nut engaging the knife near its inner end, a rotatable screw threaded in said nut to feed the knife outwards from the axis about which the cut-ofi rotates and against the friction of the clamp, characterised by means for rotating the screw comprising a ratchet wheel coupled to the screw (for example a gear wheel is fixed to the screw to rotate it for knife-feeding and engaged by a further gear wheel attached to the ratchet wheel) a pawl for rotating the ratchet wheel, a pawl operating rod reciprocable along the said axis and means arranged to reciprocate the rod at intervals to cause operation of the pawl.

The rod may be reciprocated by a solenoid having a plunger which moves to strike the rod, and a spring to cause the return movement. Alternatively a slow speed motor carrying a cam may be employed, the cam being I arranged to move the rod in one direction and a return spring being provided as before. Manually operated devices may be provided to cause the knife to feed at any desired rate when a new knife has been inserted and is brought up to contact with a grinding wheel. The pawl may rotate the ratchet wheel for knife feeding when the rod is moved by the plunger or cam or be operated by a spring which returns said rod after it has been moved.

Manual means may be provided for rotating the screw to move the nut back after a knife has been fed out to the full extent. When the machine is working, the knife feed is automatic and it is necessary to stop the movement of the nut when the limit of the knife movement is reached. For this purpose the screw has a plain part of reduced diameter at the outer end for a distance at least equal to the thickness of the nut and a leaf spring is arranged at a distance from the thread slightly less than the nut thickness. As the nut disengages from the last thread of the screw, the spring exerts a light pressure on it and thus as the screw is manually rotated to carry the nut back to the inner end of the screw the spring will press the nut into engagement with the thread.

The invention will now be more fully described with reference to the accompanying drawings, in which:

FIGURE 1 is a front elevation of a well-known type of cut-off showing the invention applied thereto, the view being partly in section,

FIGURE 1A is a side elevation of a fragment of FIG- URE 1 drawn to a larger scale,

FIGURE 2 is a section on the line 2-2, FIGURE 1,

3,159,43i Patented Feb. 16, 1965 FIGURES 3 and 4 show details of devices for moving the pawl-operating rod.

Referring to the drawings, a shaft 10 is journalled in a box 11 and rotated at one revolution per cigarette to be cut. At 13 there is pivoted to the shaft 10 a knife carrier 14 and this is in turn pivoted at 15 to a fork 16 which has a hollow shaft 17 journalled and freely rotatable in a bearing block 18. This block is adjustable on a fixed bracket 19 having a curved face so that the angle between the axes of shafts 10 and 17 can be varied. This adjustment causes the traverse of a knife 20 attached to the carrier 14 to be altered.

The linear speed of the cigarette rod in the cigarette machine on which this cut-01f is used is normally kept constant and different lengths of cigarettes are obtained by altering the speed of rotation of the shaft 10; the longer the cigarette the more slowly the shaft revolves. Thus a knife to cut a long cigarette takes longer to pass through the rod and the traverse of the knife must be altered to suit. In other words during the time the knife takes to pass through the rod the rod has advanced by a certain amount and the knife traverse must, during cutting, equal this amount.

The knife 20 as shown in FIGURE 1 is supported by a block 23 and held frictionally between plates 24 and 25. The block 23 which constitutes a nut can be raised in a guide 26, FIGURE 1A, by a screw 27 which is rotated as explained later. Thus, as the screw rotates, the knife will be moved outwards from the axis of shaft 17, sliding through the friction clamp formed by plates 24 and 25. It will of course be understood that the knife movement is extremely slow. A pin or lug 23A on the block passes through a hole in the knife blade and prevents the knife from being flung out by centrifugal force.

The screw 27 is rotated by gearing comprising a gear wheel 28 engaging an idler gear wheel 29 which is driven by a gear wheel 30. The gear wheel 30 is fixed to a short shaft 31 which also has a ratchet wheel 32 fixed to it.

A solenoid 33 is supported in the end of the bearing block 18 and the bracket 19 has a large clearance space to permit the solenoid to move round when it is desired to alter the angle of inclination of the shaft 17 and thus the stroke of the knife 20. The solenoid has a plunger 34 which is projected when the solenoid is energized and this plunger is in alignment with a rod 35, the pawl-operating rod. Current is supplied to the coil of the solenoid as related later with reference to FIGURE 3.

The rod is pivoted to one end of a lever 36 which is pivoted at 37 and the upper end of the lever has a pawl 38 having a tooth 40 pivoted on it at 39, FIGURE 2.

The pawl tooth engages the ratchet wheel 32 and rotates it as the pawl moves to the right in FIGURE 2. A leaf spring 41 keeps the pawl in operative engagement with the teeth of the ratchet wheel. A detent pawl or click 42 is also provided pivoted at 43 and pressed to engage the teeth of the ratchet wheel 32 by a spring 44. The lever 36 is swung on its pivot when the rod 35 is struck by the plunger 34 and the tooth 40 rotates the ratchet wheel 32 and the screw 27 is therefore rotated 21 small amount to feed the knife outwards. A spring 45 moves the lever 36 back to the position shown in the drawing.

Referring now to FIGURE 3, current is fed to the coil of the solenoid 33 from a battery 45A, one terminal of which is directly connected to an end of the coil while the other terminal is connected to a brush 46 which rubs on a contact disc 47, connected, as shown, to a segment 48 on an insulating disc 49. The disc is rotated at any desired rate by gearing (not shown) which connects the shaft 50 to any suitable part of the machine,

or the cut off. An impulse every two minutes is sufiicient to feed a knife for a machine making 1500 cigarettes by another lead from the battery to said other end ofthe coil. A switch 52 in the lead enables the solenoid to be rapidly operated.

In FIGURE 4 a crown cam 53 attached to a shaft 53A driven by a slow speed motor 54, presses the rod 35 to the left at each rotation, which occurs every two minutes. If it is desired to accelerate the knife feeding the shaft is manually rotated by a handwheel 55, the bracket 19 being suitably modified, and the motor gearing being suitable to permit this. 7

The rate of knife feeding is arbitrary, depending on the knife, the grinder, the work done and the users requirements. With knives and grinders now available satisfactory'operation of the cut-off on cigarette rod can be obtained with as little as one movement. of rod 35 per two minutes. If filter rods are being cut more frequent grinding is necessary.

' As the nut 23 moves up the screw it would eventually jam against the end of the guide 26, since the feeding of the knifeis automatic. To prevent this the screw thread finishes some distance away from the end of the guide 26 so the nut will ride free on the plain end of the screw. To ensure that the nut re-engages with the thread of the screw when the latter is rotated in the opposite direction, as explained below, to move the nut to the inner end of the screw, a leaf spring 56, FIGURE 1A, is

provided which straddles the plain end of the screw and presses the nut against the thread so that it easily reengages when the screw is rotated. I

When the knife has been fed out and ground away to the limit it is removed and it is then necessary to wind the nut back to the inner position, that is, near to the shaft 10. This is done by applying a spanner to a square on the end of the screw rod. It is first necessary to disengage tooth 40 and click 42 from the ratchet wheel and this is done by rotating a small cam 57, FIGURE 2, by a'stem 58, FIGURE 1.

It will be seen that the rod 35 is coaxial with the shaft 17 and that this shaft is an axis about which the cut-off rotates. This shaft is an essential feature of the cut-off shown but it will be readily understood that where the cut-off is fixed to a shaft such as lfltand thus rotates about the axis of the pawl operating rod would be housed in said shaft 10 and coaxial with it. A cut-off of this latter kind secures the desired knife-traverse by a bodily reciprocation of the cut-off and its shaft.

What I claim as my invention and desired to secure by Letters Patent is:

1. In a cigarette cut-01f for a continuous rod cigarettemaking machine having a sickle knife rotatable about an axis parallel with the rod, a device for feeding the knife radially outwards to compensate for wear of the cutting edge of the knife, comprising a knife clamp frictionally gripping the knife, a nut engaging the knife near its radially inner end, a radially extending screw passing through the nut and having an unthreaded reduced diameter portion at its outer end, a ratchet wheel for rotating the screw, a pawl for rotating the ratchet wheel, reciprocable means for operating the pawl and comprising a rod reciprocable along said axis, means to reciprocate the rod at intervals to operate the pawl and thereby to rotate the screw and feed the nut and knife radially outwards along the screw against the frictional resistance of the knife clamp until the nut is driven on to the unthreaded portion of the screw to provide a limit for the outward feed of the knife, 2. spring against which the nut bears when it reaohes the unthreaded portion of the screw to hold the nut against the threaded portion of the screw, manually-operable means for disengaging the pawl and manually operable means for rotating said screw in the opposite direction to re-engage the nut and return it towards the radially inner end of the screw.

2. A device as claimed in claim 1 wherein the means to reciprocate the rod comprises a cam to move the rod in one direction, a motor to rotate the cam and comprising gearing, a spring to effect the return movement of the rod,

and manual means to rotate the cam.

3. A device as claimed in claim 1 wherein the means to reciprocate the rod comprises a solenoid having a plunger to strike the rod when the solenoid is energised to move the rod in one direction and aspring to effect return movement of the rod, a source of electricity, a first switch for connecting the electrical source to the solenoid at timed intervals and a second and manually-operable switch in parallel with the first switch.

References Cited by the Examiner UNITED STATES PATENTS 2,175,497 10/39 Wilbur 83-556 FOREIGN PATENTS 501,093 8/53 Italy.

ANDREW R. JUHASZ, Primary Examiner.

HUNTER C. BOURNE, JR., Examiner. 

1. IN A CIGARETTE CUT-OFF FOR A CONTINUOUS ROD CIGARETTEMAKING MACHINE HAVING A SICKLE KNIFE ROTATABLE ABOUT AN AXIS PARALLEL WITH THE ROD, A DEVICE FOR FEEDING THE KNIFE RADIALLY OUTWARDS TO COMPENSATE A KNIFE CLAMP CUTTING EDGE OF THE KNIFE, A NUT ENGAGING THE KNIFE FRICTIONALLY GRIPPING THE KNIFE, A NUT ENGAGING THE KNIFE NEAR ITS RADIALLY INNER END, A RADIALLY EXTENDING SCREW PASSING THROUGH THE NUT AND HAVING AN UNTHREADED REDUCED DIAMETER PORTION AT ITS OUTER END, A RATCHET WHEEL FOR ROTATING THE SCREW, A PAWL FOR ROTATING THE RATCHET WHEEL, RECIPROCABLE MEANS FOR OPERATING THE PAWL AND COMPRISING A ROD RECIPROCABLE ALONG SAID AXIS, MEANS TO RECIPROCATE THE ROD AT INTERVALS TO OPERATE THE PAWL AND THEREBY TO ROTATE THE SCREW AND FEED THE NUT AND KNIFE RADIALLY OUTWARDS ALONG THE SCREW AGAINST THE FRICTIONAL RESISTANCE OF THE KNIFE CLAMP UNTIL THE NUT IS DRIVEN ON TO THE UNTHREADED PORTION OF THE SCREW TO PROVIDE A LIMIT FOR THE OUTWARD FEED OF THE KNIFE, A SPRING AGAINST WHICH THE NUT BEARS WHEN IT REACHES THE UNTHREADED PORTION OF THE SCREW TO HOLD THE NUT AGAINST THE THREADED PORTION OF THE SCREW, MANUALLY-OPERABLE MEANS FOR DISENGAGING THE PAWL AND MANUALLY OPERABLE MEANS FOR ROTATING SAID SCREW IN THE OPPOSITE DIRECTION TO RE-ENGAGE THE NUT AND RETURN IT TOWARDS THE RADIALLY INNER END OF THE SCREW. 